Meghnad Saha

“The impetus given to astrophysics by Saha’s work can scarcely be overestimated, as nearly all later progress in this field has been influenced by it and much of the subsequent work has the character of refinements of Saha’s ideas.”- S.Rosseland

One of the most important scientific theories during the 20th century, has been the theory of thermal ionization.  Basically an expression, that relates the ionization state of  a gas, in thermal equilibrium to the temperature and pressure. It combined the theories of  quantum mechanics and statistical mechanics and is used to explain the spectral classification of stars. Arthur Stanley Eddington, called it as one of the most important landmark in the history of astronomy.

The man who developed the theory, after whom it is named, is one of the greatest Indian scientists of the modern era, Meghnad Saha. He founded nuclear physics as a discipline in India, also built the first cyclotron in India. The National Academy of Sciences, Allahabad, Indian Physical Society, Kolkata were founded by him, an equally great institution builder too.He ws also an MP for some time, and the Damodar Valley Project was his idea. He contributed a lot to river planning, management, and some of his ideas were quite visionary.

This remarkable genius was was born on October 6, 1893 in a rather poor family at a small village near Dhaka. His father Jagannath, a petty shopkeeper, did not even have the money to educate his children. His elder brother had to drop out and work in a jute mill, while his other brother too had to discontinue education, and help his father in the shop. Saha studied in the village primary school for some time, and demonstrated an excellent aptitude for learning.  His parents however could not afford to educate him further, and his father saw no use either.

However his brother came to his aid, and with the help of a kind hearted doctor, Ananta Kumar, he managed to study at Simula . The doctor gave him free lodging and boarding, for which Saha in return ran some odd errands.  With help from his brother and the Purba Banga Baisya Samiti, Saha managed to complete his education later at Collegiate School, Dhaka.  He was passionate about Maths as well as History and literature at school. His favorite books were Tagore’s Katha o Kahani about Rajput, Maratha warriors, Michael Madusudhan Dutt’s Meghnad Badh Kavya along with Todd’s Annals on Rajasthan.

However Saha had to leave Collegiate School, due to his participation in Swadeshi Movement. He later got his Indian School Certificate from Dhaka College. He soon joined Presidency, Kolkata, where his class mates included S.N.Bose while P.C.Mahalanobis was his senior.  He was fortunate enough to have teachers like J.C.Bose( Physics), P.C.Ray( Chemistry) while at Presidency. It was his interaction with them, that influnced his thoughts, value system and career too. In a way Presidency was a hub of the Bengal Renaissance.

After graduating from Presidency, Saha joined Univ College of Science, as an Applied Maths lecturer. Later Saha along with S.N.Bose joined the Physics Dept at Kolkata Univ, and C.V.Raman joined them later. He had to struggle with lack of equipment in Kolkata University then to do his research work, there was no guide too. And neither did he have enough money to pay for the publication of his research paper in a foreign journal. Nevertheless this did not prevent Meghnad Saha from continuing his research, work in Physics on a varied range of topics. Between 1917-19, he published 10 different papers in Physics on topics ranging from Maxwell’s Stresses to Quantum Theory.

It was around this time too that Meghnad Saha began his work on astrophysics, reading  the works of Planck, Bohr and Sommerfield. Along with S.N.Bose he also published an English translation of Theory of Relativity, and got it done in a book form too. His work on Stellar Spectra, got him the Premchand Roy Scholarship from Kolkata University, that enabled him to go abroad. In Europe, Saha, first worked under Albert Fowler in London, and later at Walter Nernst’s Lab in Berlin.

It was during his stay at Berlin, that Meghnad Saha came up with landmark theory of Thermal Ionization, named after him later. On his return to India, he worked for some in Kolkata University, before moving out to Allahabad University. His work on the thermal ionization, led to what is now called the Saha-Langmuir equation in Astrophysics. Basically it is an expression that relates ionization state of a gas in thermal equilibrium to temperature and pressure. The Saha equation has become one of the basic tools for interpretation of spectra of stars in astrophysics. In fact the term “to Saha correctly” is a tribute to him in that field, indicating a correct interpretation, one of the rare Indian scientists to have that honor.

It must be noted that Meghnad Saha derived the Saha equation with very meagre laboratory equipment, practically no data. It was just through plain observation and derivatio, outstanding achievement against all odds. On his return to India, he worked for some in Kolkata University, before moving out to Allahabad University. His decision to leave Kolkata Univ was due to the meagre grants then given for pursuing research. Again at Allahabad University,Meghnad Saha improved the workshop, library, and managed to churn out quality research papers along with his students. Along with astrophysics, he also conducted research on other topics of physics too.

It was at Allahabad University, that Meghnad Saha, came up with his landmark publication A Treatise on Heat in 1931, which he wrote along with C.V.Raman and B.N.Srivastava, that  remains one of the most important books in Physics to date. He rejoined Kolkata Univ in 1938, around the time when Dr.Shyamprasad Mukherjee was the VC, and restructed the Post Grad syllabus in Physics. He also set up the Dept of Radio Physics, Applied Electronics at Kolkata University, built many institutions.

The Institute for Nuclear Physics, Kolkata was founded by Meghnad Saha in 1950, foundation stone was laid by Shyama Prasad Mukherjee. He also founded the Indian Science News Association, in 1935, for the purpose of spreading scientific education among public. Saha, like most other modern Indian scientists, was a first rate institution builder. Some of them that owe their growth to him were National Academy of Science, Indian Physical Society and IISc. He was also director at Indian Association for Cultivation of Science.

He had a close association with Netaji who was impressed with his work on science, as well as on flood relief. The Damodar Valley Committee was formed due to Saha’s writings on the devastating effect of floods in Bengal, and parts of Jharkhand. He deeply believed in large scale industrialization, and use of science and technology, for the development and growth of India.

I had lived in ivory tower up to 1930. But science and technology are as important for administration now-a-days as law and order. I have gradually glided into politics because I wanted to be of some use to the country in my own humble way.- Meghnad Saha

In 1952, he was elected as an Independent MP from Kolkata North West, made his voice heard in Parliament. He actually defeated a powerful and well funded Congress candidate Prabhu Dayal Himatsingka, funding his campaign from the proceeds he got from sale of his textbook on Heat. Yet he won by more than 16% margin, such was his stature. As an MP too, Meghnad Saha, made an active contribution in Parliament, on areas like Education, River Projects, Atomic Energy etc. He was known for his very incisive analysis of issues, without being unduly critical, and his questioning of the Govt on critical issues.

“Meghnad Saha’s ionization equation which opened the door to stellar astrophysics was one of the top ten achievements of 20th century Indian science and could be considered in the Nobel Prize class.”- Jayant Narlikar

Saha also remains one of the Indian Scientists, who was bypassed for the Nobel Physics around 7 times. The comittee felt his landmark work on Ionization was a good application but not discovery.

Meghnad Saha passed away on February 16,1956 due to a heart attack in New Delhi. He had been suffering from hypertension from long. Yet his legacy would forever remain in the Saha Equation, and the institutions he developed, and his book on Heat.